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US3956202A - Process for preparing low smoke-generating rigid polyurethane foam - Google Patents

Process for preparing low smoke-generating rigid polyurethane foam Download PDF

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US3956202A
US3956202A US05/464,633 US46463374A US3956202A US 3956202 A US3956202 A US 3956202A US 46463374 A US46463374 A US 46463374A US 3956202 A US3956202 A US 3956202A
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starch
polyol
rigid polyurethane
polyisocyanate
smoke
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US05/464,633
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Kazuo Iwasaki
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Achilles Corp
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Kohkoku Chemical Industry Co Ltd
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Priority claimed from JP12807773A external-priority patent/JPS5542092B2/ja
Priority claimed from JP742582A external-priority patent/JPS5622892B2/ja
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
    • C08J2375/04—Polyurethanes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2401/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2403/00—Characterised by the use of starch, amylose or amylopectin or of their derivatives or degradation products
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S521/00—Synthetic resins or natural rubbers -- part of the class 520 series
    • Y10S521/903—Cellular polymer having reduced smoke or gas generation

Definitions

  • the present invention relates to a process for preparing a low smoke-generating rigid polyurethane foam.
  • Rigid polyurethane foam has been extensively used as thermal insulating material, light weight constructing material and floating material due to its excellent properties for such purposes.
  • large evolution of smoke because the materials are made from plastics in which polyurethane is the major constituent, restricts its use for constructural material to a considerable extent. Consequently, the problem arises as to how to reduce the amount of smoke generated in order to extend the use of rigid polyurethane foams.
  • solid carboxylic acids such as adipic, fumaric and HET (chlorendic) acids are added to the rigid polyurethane foam in the course of preparation, as exemplified in U.S. Pat. Nos. 3,637,542, 3,639,307 and 3,647,724.
  • the present invention intends to overcome these troubles.
  • the process proposed in this invention involves addition of a powdery polymer of glucose and/or a derivative thereof to the raw material on preparing a rigid polyurethane foam.
  • the polyurethane foam prepared by the process of this invention evolves a half or less smoke relative to ordinary polyurethane foams.
  • a polymer of glucose which is of a polymerized-glucose structure and contains hydroxy groups in the molecule, is chemically inactive toward both polyols and tertiary amines which compose the raw material for polyurethane foams. Therefore chemical reactions between these ingredients are not encountered while mixing.
  • the situation is true also for the polyisocyanate and the mixture does not gell in a shorter time.
  • a polymer of glucose can be thoroughly dispersed, though not dissolved, in the raw material for polyurethane foams, and therefore the mixture can be applied to the material for polyurethane foams without forming a precipitate if it is continuously stirred.
  • the process of this invention for preparing low smoke-generating rigid polyurethane foams essentially resides in adding a powdered polymer of glucose and/or a derivative thereof to the raw material for polyurethane foams at room temperature.
  • the proportions of ingredients in the mixture should be approximately equal in chemical equivalents.
  • the amount of polyisocyanate in equivalents should be approximately equal to the amounts in equivalents of the polyol and the blowing agent which react with the polyisocyanate.
  • the polymer of glucose need not be considered in the calculation of the equivalents, because the hydroxy groups in a polymer of glucose do not substantially react.
  • the ratio in equivalents of polyisocyanate to other substances which react with polyisocyanate should be less than 2 : 1, preferably less than 1.5 : 1 and the lower limit thereof be about 1 : 1. Presence of an excessive amount of polyisocyanate results either in the formation of isocyanurate rings which contain more heat resistant bonding than those in the urethane, when a catalyst for forming isocyanurate is present, leading to more evolution of smoke on combustion, or in a decreased formation of desired polymers due to the presence of an excess of isocyanate in the absence of the catalyst.
  • a polymer of glucose and/or derivative thereof should be in the form of a fine powder. More particularly they should be finer than 20 mesh, preferably finer than 42 mesh. The finer the particle size of the polymer of glucose and/or derivative thereof, the better is the dispersion and stability in the mixture and the uniformity of the foam obtained.
  • Glucose polymers and/or derivative thereof to be used in this invention include cellulose and/or derivatives thereof and starch and/or derivatives thereof.
  • Any cellulose and derivatives thereof which are powdery at room temperature can be used in the present invention; which includes crystalline cellulose, non-crystalline (or amorphous) cellulose and the mixture thereof in an arbitrary proportions.
  • Derivatives of cellulose, such as, alkyl cellulose and carboxymethyl cellulose may be used.
  • Alkyl cellulose such as, methyl cellulose, ethyl cellulose and propyl cellulose may be used either alone or in the combination of more than two members.
  • carboxymethyl cellulose cellulose ethers prepared by the reaction of alkali cellulose with chloroacetic acid may be used; practically effective is sodium carboxymethyl cellulose, or sodium cellulose glycolate.
  • Starch and/or any derivatives thereof which are/is powder at room temperature could be used in this invention. These substances include natural starch, esteric and etheric derivatives of starch. Natural starch, a high molecular substance from D-glucose molecules intercombined to form ⁇ -1,4-glucoside, is a mixture of amylose in a straight chain structure and amylopectin in a branched structure. Any proportion of amylose to amylopectin in starch is allowed for use to the purpose of this invention, therefore all natural starch may be used. Natural starch includes, glutinous rice, rice, wheat, corn, glutinous corn, potato, sweet potato, sago, tapioca, banana and arrowroot starch.
  • the starch derivatives used in this invention include acetylated, nitrated, methylated and carboxymethylated starch.
  • Acetylated starch contains acetyl groups of an arbitrary content which have substituted 1 to 3 hydroxyl groups on each intermediate glucose rings, while methylated starch contains methyl groups of an arbitrary content which have substituted 1 to 3 hydroxyl groups on each intermediate glucose rings.
  • Methylated starch containing more methoxyl groups is more soluble and more dispersible in the raw materials (for example, polyols and water) of rigid polyurethane foams.
  • addition of more than 5 % of a polymer of glucose and/or a derivative thereof is sufficient to suppress the amount of evolved smoke to less than a half of that otherwise expected.
  • Polymers of glucose and/or derivatives thereof contain many oxygen atoms in their chemical formula and therefore when added to rigid polyurethane foams they act to assist carbonization of the surface of polyurethane foams on combustion. More particularly, polymers of glucose and/or derivatives thereof are dispersed in the raw material for preparing rigid polyurethane foams and are present also in the surface layer when foamed. On combustion, these polymers of glucose and/or derivatives thereof are rapidly burnt to carbonization which cover the surface of the foams and prevent further combustion into the inner layers, thus giving the flame retardancy property. Owing to the rapid burning of the surface of rigid polyurethane foams due to the action of polymers of glucose and/or derivatives thereof, less amount of smoke is evolved than otherwise.
  • Raw materials commonly used in ordinary rigid polyurethane foams can also be used as the raw materials for the rigid polyurethane foams in the present invention.
  • the raw materials for preparing rigid polyurethane foams which include a polyisocyanate, polyols having more than 3 hydroxyl groups in a molecule and a hydroxyl value greater than 100, catalyst, surfactant, blowing agent and flame retardant if necessary, can be used for the present purpose.
  • polyether-polyols prepared by an addition reaction of one or more alkylene oxides (such as ethylene oxide, propylene oxide and butylene oxide) with glycerine, trimethylolpropane, pentaerythrit, sorbit, sucrose, ethylenediamine and 4,4'-diaminodiphenylmethane can be used as a reaction initiator.
  • alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide
  • polyester-polyols having end hydroxyl groups which are prepared by a condensation reaction of polycarboxylic acid, such as, adipic acids and phthalic acids with a polyhydroxyl alcohol, such as, ethyleneglycol and trimethylolpropane.
  • the polyols used should contain more than 3 hydroxyl groups per molecule and the hydroxyl value greater than 100, preferably than 150. If the number of hydroxyl groups is smaller or the hydroxyl value is lower than the said values, a lower degree of cross-linking will probably result and consequently practical sufficient strength and dimensional stability in rigid polyurethane foams can not be obtained.
  • the polyols may be used either alone or in combination of any two or more.
  • Polyisocyanates available for the purpose include tolylenediisocyanate (hereinafter designated TDI), 4,4'-diphenylmethanediisocyanate (hereinafter designated MDI) and hexamethylenediisocyanate, among which crude materials of TDI and MDI are particularly useful. Further, a prepolymer having end isocyanate groups may be used which can be prepared by the reaction of the above polyisocyanate in an excessive amount with a polyol containing more than 2 hydroxyl groups per molecule.
  • TDI tolylenediisocyanate
  • MDI 4,4'-diphenylmethanediisocyanate
  • hexamethylenediisocyanate among which crude materials of TDI and MDI are particularly useful.
  • a prepolymer having end isocyanate groups may be used which can be prepared by the reaction of the above polyisocyanate in an excessive amount with a polyol containing more than 2 hydroxyl groups per
  • Useful catalysts include tertiary amine, such as, triethylamine, triethylenediamine and pentamethyldiethylenetriamine, and/or organometallic compounds, such as, dibutyltindilaurate, dibutyltindiacetate, potassium acetate and potassium propionate.
  • Surfactants include non-ionic surfactants such as, polyoxyalkylenealkylether and polyoxyalkylenealkylaminoether and/or silicone oils, such as, organo-polysiloxane and siloxane-oxyalkylene copolymers.
  • Blowing agents used in the present invention include reactive blowing agents (such as water and nitroalkanes) which evolve carbon dioxide on reaction with isocyanate and/or low boiling solvents, such as, trichloromonofluoromethane and dichlorodifluoromethane.
  • Flame retardant used include phosphoric esters, such as, tricresyl phosphate, tris(2-chloroethyl)phosphate, tris (chloropropyl) phosphate, O,O-diethyl-N,N,-bis(2-hydroxyethyl)-aminomethyl phosphonate and/or metal oxides, such as, antimony oxide, alumina and antimony oxychloride.
  • ingredients of the reaction mixture and polymers of glucose and/or derivatives thereof may be mixed to form a uniform mixture. Either batch or continuous operations may be used. Mechanical mixing by mixing of high pressure-jet streams of ingredients and spraying of the ingredients at a high or low pressure are all recommended. Consequently, polymers of glucose to be used in the present invention may be mixed beforehand in the reaction mixture (containing either polyisocyanate or components other than polyisocyanate) and all the ingredients are mixed at a time to produce rigid polyurethane foams. Alternatively, powders of polymers of glucose may be transported in a separate route and sprayed in a jet to prepare a reaction mixture.
  • both the reaction mixture and polymers of glucose may be separately sprayed in jets for complete thorough mixing in the air.
  • the most important is to obtain a uniform mixture whatever the methods of mixing and agitation may be.
  • the physical properties of the foam may have localized variations, leading to local shrinkage or swelling, which should be undoubtedly avoided in the products.
  • the rigid polyurethane foam produced by the process of this invention exhibits excellent property of low smoke-generation.
  • the smoke-generation coefficient per unit areas (expressed hereinafter by C.sub. A) of the foams produced by the present invention, as determined by the testing method in JIS A-1321 was less than a half of those for conventional rigid polyurethane foams.
  • the foams produced by the process of this invention exhibit not only an excellent property of low smoke-generation, but also light weight, high strength, excellent thermal insulation and dimensional stability which essentially belong to the properties of general rigid polyurethane foams. Therefore, the foams of this invention can be widely applied to constructural material, thermal insulating material and lightweighted structural material either alone or in a sandwich or a laminated structure with colored iron plates, zinc plated iron plates, gypsum boards, asbestos slate boards and sheets of paper.
  • Crude MDI is a crude product of diphenylmethane diisocyanate containing 31% of isocyanate groups;
  • Polyol A is a polyether-polyol of a hydroxyl value of 450 prepared by adding propylene oxide to sucrose as an initiator, and
  • Polyol B is a polyether-polyol of a hydroxyl value of 500 prepared by adding propylene oxide to sorbit as an initiator;
  • Silicone oil is a silicone surfactant (SH-193 supplied from Toray Silicone Co.);
  • Methyl cellulose is a product prepared by substituting about 30% of the hydroxyl groups in cellulose by methoxyl groups and a 2% aqueous solution thereof possesses a viscosity of 100 poise (at 20°C), the particle size being approximately 60 mesh;
  • Potato starch is a commercially available starch which is then dried for 3 hours at 120°C (the particle size being about 270 mesh): Corn starch is commercially available starch
  • FIG. 1 shows the relation between amounts in percentage by weight of methyl cellulose added and the smoke-generation coefficient (C A ).
  • FIGS. 2 and 3 show the relation between amounts in percentages by weight of starch added and the smoke-generation coefficient (C A ).
  • Curve A Curve expressing the smoke-generation coefficients when the ratio in chemical equivalents is 1.05.
  • Curve B Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 2.00.
  • Curve C Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 3.00.
  • Curve D Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 1.05.
  • Curve E Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 3.00.
  • Curve F Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 4.00.
  • Curve G Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 1.05.
  • Raw materials itemized in Table 1 were weighed in a 1 liter polyethylene beaker which, after vigorous agitation for 20 sec. with a cage-like mixer (3,400 rpm), were foamed in a wooden box, to obtain foamed matter.
  • Example 3 In place of the methyl cellulose in Example 3 above, fine crystalline powders of sodium carboxymethyl cellulose and cellulose (particle size of both of the compounds was about 100 mesh) were used respectively. Foams produced in the same process gave results shown in Table 2. The C A values of both foams were less than a half of those for conventional rigid polyurethane foams.
  • Methyl cellulose in Example 3 above was replaced by a polyhydroxyl alcohol or a succharide which was solid at room temperature, such as, sucrose, pentaerythrit, mannit and glucose. In neither case could the smoke-generating property be effectively reduced. Results are shown in Table 2.
  • a mixture consisting of the followng components was foamed in the same manner as in Example 1, to obtain a foam.
  • Curves D, E and F correspond to the ratio in chemical equivalents 1.05, 3.00 and 4.00, respectively.
  • the smoke-generation coefficients are larger on Curve E than on Curve D, and larger on Curve F than on Curve E, as is readily seen from the figure.
  • the amount of starch used exceeds 30%, it may be impossible that a mixture of raw materials can be agitated owing to much increased viscosity to produce uniform rigid polyurethane foams.
  • Foams were prepared in the same manner as in Example 17 except tris(2-chloroethyl) phosphate (10 parts).

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Abstract

A process for preparing rigid polyurethane foam in which the major ingredients are a polyisocyanate, a polyol having more than three hydroxy groups and a hydroxyl value greater than 100, and blowing agents, comprising adjusting the ratio of the chemical equivalent of polyisocyanate to the polyol and blowing agent which react with the polyisocyanate to the range between 2 : 1 and 1 : 1, and adding a polymer of glucose and/or a derivative thereof in the form of a powder in the amount exceeding 5% by weight.

Description

DETAILED EXPLANATION OF INVENTION
The present invention relates to a process for preparing a low smoke-generating rigid polyurethane foam. Rigid polyurethane foam has been extensively used as thermal insulating material, light weight constructing material and floating material due to its excellent properties for such purposes. However, large evolution of smoke, because the materials are made from plastics in which polyurethane is the major constituent, restricts its use for constructural material to a considerable extent. Consequently, the problem arises as to how to reduce the amount of smoke generated in order to extend the use of rigid polyurethane foams.
As a measure to reduce the amount of smoke generated, solid carboxylic acids, such as adipic, fumaric and HET (chlorendic) acids are added to the rigid polyurethane foam in the course of preparation, as exemplified in U.S. Pat. Nos. 3,637,542, 3,639,307 and 3,647,724. Although the method makes it possible to reduce the amount of smoke generated to a half of its original value, these acids which are chemically active toward some ingredients of the polyurethane foam, such as the polyisocyanate, polyol and tertiary amine catalyst, may probably react with these ingredients while being remixed, leading to deterioration of the raw materials while being stored and to precipitation and solidification of solid carboxylic acids in the raw materials. Therefore the method is not yet applied in practical use.
The present invention intends to overcome these troubles. The process proposed in this invention involves addition of a powdery polymer of glucose and/or a derivative thereof to the raw material on preparing a rigid polyurethane foam. The polyurethane foam prepared by the process of this invention evolves a half or less smoke relative to ordinary polyurethane foams. A polymer of glucose, which is of a polymerized-glucose structure and contains hydroxy groups in the molecule, is chemically inactive toward both polyols and tertiary amines which compose the raw material for polyurethane foams. Therefore chemical reactions between these ingredients are not encountered while mixing. The situation is true also for the polyisocyanate and the mixture does not gell in a shorter time. Further a polymer of glucose can be thoroughly dispersed, though not dissolved, in the raw material for polyurethane foams, and therefore the mixture can be applied to the material for polyurethane foams without forming a precipitate if it is continuously stirred.
The process of this invention for preparing low smoke-generating rigid polyurethane foams essentially resides in adding a powdered polymer of glucose and/or a derivative thereof to the raw material for polyurethane foams at room temperature. The proportions of ingredients in the mixture should be approximately equal in chemical equivalents. In other words, the amount of polyisocyanate in equivalents should be approximately equal to the amounts in equivalents of the polyol and the blowing agent which react with the polyisocyanate. The polymer of glucose need not be considered in the calculation of the equivalents, because the hydroxy groups in a polymer of glucose do not substantially react. The ratio in equivalents of polyisocyanate to other substances which react with polyisocyanate (exclusive of polymers of glucose) should be less than 2 : 1, preferably less than 1.5 : 1 and the lower limit thereof be about 1 : 1. Presence of an excessive amount of polyisocyanate results either in the formation of isocyanurate rings which contain more heat resistant bonding than those in the urethane, when a catalyst for forming isocyanurate is present, leading to more evolution of smoke on combustion, or in a decreased formation of desired polymers due to the presence of an excess of isocyanate in the absence of the catalyst.
A polymer of glucose and/or derivative thereof should be in the form of a fine powder. More particularly they should be finer than 20 mesh, preferably finer than 42 mesh. The finer the particle size of the polymer of glucose and/or derivative thereof, the better is the dispersion and stability in the mixture and the uniformity of the foam obtained.
Glucose polymers and/or derivative thereof to be used in this invention include cellulose and/or derivatives thereof and starch and/or derivatives thereof.
Any cellulose and derivatives thereof which are powdery at room temperature can be used in the present invention; which includes crystalline cellulose, non-crystalline (or amorphous) cellulose and the mixture thereof in an arbitrary proportions. Derivatives of cellulose, such as, alkyl cellulose and carboxymethyl cellulose may be used.
Alkyl cellulose such as, methyl cellulose, ethyl cellulose and propyl cellulose may be used either alone or in the combination of more than two members.
As carboxymethyl cellulose, cellulose ethers prepared by the reaction of alkali cellulose with chloroacetic acid may be used; practically effective is sodium carboxymethyl cellulose, or sodium cellulose glycolate.
Starch and/or any derivatives thereof which are/is powder at room temperature could be used in this invention. These substances include natural starch, esteric and etheric derivatives of starch. Natural starch, a high molecular substance from D-glucose molecules intercombined to form α-1,4-glucoside, is a mixture of amylose in a straight chain structure and amylopectin in a branched structure. Any proportion of amylose to amylopectin in starch is allowed for use to the purpose of this invention, therefore all natural starch may be used. Natural starch includes, glutinous rice, rice, wheat, corn, glutinous corn, potato, sweet potato, sago, tapioca, banana and arrowroot starch.
The starch derivatives used in this invention include acetylated, nitrated, methylated and carboxymethylated starch. Acetylated starch contains acetyl groups of an arbitrary content which have substituted 1 to 3 hydroxyl groups on each intermediate glucose rings, while methylated starch contains methyl groups of an arbitrary content which have substituted 1 to 3 hydroxyl groups on each intermediate glucose rings. Methylated starch containing more methoxyl groups is more soluble and more dispersible in the raw materials (for example, polyols and water) of rigid polyurethane foams.
In the present invention, addition of more than 5 % of a polymer of glucose and/or a derivative thereof is sufficient to suppress the amount of evolved smoke to less than a half of that otherwise expected.
Polymers of glucose and/or derivatives thereof contain many oxygen atoms in their chemical formula and therefore when added to rigid polyurethane foams they act to assist carbonization of the surface of polyurethane foams on combustion. More particularly, polymers of glucose and/or derivatives thereof are dispersed in the raw material for preparing rigid polyurethane foams and are present also in the surface layer when foamed. On combustion, these polymers of glucose and/or derivatives thereof are rapidly burnt to carbonization which cover the surface of the foams and prevent further combustion into the inner layers, thus giving the flame retardancy property. Owing to the rapid burning of the surface of rigid polyurethane foams due to the action of polymers of glucose and/or derivatives thereof, less amount of smoke is evolved than otherwise.
Raw materials commonly used in ordinary rigid polyurethane foams can also be used as the raw materials for the rigid polyurethane foams in the present invention. Namely, the raw materials for preparing rigid polyurethane foams, which include a polyisocyanate, polyols having more than 3 hydroxyl groups in a molecule and a hydroxyl value greater than 100, catalyst, surfactant, blowing agent and flame retardant if necessary, can be used for the present purpose.
Any polyol which is used for preparing ordinary rigid polyurethane foams can also be used in this invention. For example, polyether-polyols prepared by an addition reaction of one or more alkylene oxides (such as ethylene oxide, propylene oxide and butylene oxide) with glycerine, trimethylolpropane, pentaerythrit, sorbit, sucrose, ethylenediamine and 4,4'-diaminodiphenylmethane can be used as a reaction initiator. Also suitable are polyester-polyols having end hydroxyl groups which are prepared by a condensation reaction of polycarboxylic acid, such as, adipic acids and phthalic acids with a polyhydroxyl alcohol, such as, ethyleneglycol and trimethylolpropane. The polyols used should contain more than 3 hydroxyl groups per molecule and the hydroxyl value greater than 100, preferably than 150. If the number of hydroxyl groups is smaller or the hydroxyl value is lower than the said values, a lower degree of cross-linking will probably result and consequently practical sufficient strength and dimensional stability in rigid polyurethane foams can not be obtained. The polyols may be used either alone or in combination of any two or more.
Polyisocyanates available for the purpose include tolylenediisocyanate (hereinafter designated TDI), 4,4'-diphenylmethanediisocyanate (hereinafter designated MDI) and hexamethylenediisocyanate, among which crude materials of TDI and MDI are particularly useful. Further, a prepolymer having end isocyanate groups may be used which can be prepared by the reaction of the above polyisocyanate in an excessive amount with a polyol containing more than 2 hydroxyl groups per molecule.
Useful catalysts include tertiary amine, such as, triethylamine, triethylenediamine and pentamethyldiethylenetriamine, and/or organometallic compounds, such as, dibutyltindilaurate, dibutyltindiacetate, potassium acetate and potassium propionate. Surfactants include non-ionic surfactants such as, polyoxyalkylenealkylether and polyoxyalkylenealkylaminoether and/or silicone oils, such as, organo-polysiloxane and siloxane-oxyalkylene copolymers. Blowing agents used in the present invention include reactive blowing agents (such as water and nitroalkanes) which evolve carbon dioxide on reaction with isocyanate and/or low boiling solvents, such as, trichloromonofluoromethane and dichlorodifluoromethane. Flame retardant used include phosphoric esters, such as, tricresyl phosphate, tris(2-chloroethyl)phosphate, tris (chloropropyl) phosphate, O,O-diethyl-N,N,-bis(2-hydroxyethyl)-aminomethyl phosphonate and/or metal oxides, such as, antimony oxide, alumina and antimony oxychloride.
In the process of the present invention, ingredients of the reaction mixture and polymers of glucose and/or derivatives thereof may be mixed to form a uniform mixture. Either batch or continuous operations may be used. Mechanical mixing by mixing of high pressure-jet streams of ingredients and spraying of the ingredients at a high or low pressure are all recommended. Consequently, polymers of glucose to be used in the present invention may be mixed beforehand in the reaction mixture (containing either polyisocyanate or components other than polyisocyanate) and all the ingredients are mixed at a time to produce rigid polyurethane foams. Alternatively, powders of polymers of glucose may be transported in a separate route and sprayed in a jet to prepare a reaction mixture. Otherwise, both the reaction mixture and polymers of glucose may be separately sprayed in jets for complete thorough mixing in the air. In the mixing operation, the most important is to obtain a uniform mixture whatever the methods of mixing and agitation may be. When a non-uniform mixture is used, the physical properties of the foam may have localized variations, leading to local shrinkage or swelling, which should be undoubtedly avoided in the products.
The rigid polyurethane foam produced by the process of this invention exhibits excellent property of low smoke-generation. Thus, the smoke-generation coefficient per unit areas (expressed hereinafter by C.sub. A) of the foams produced by the present invention, as determined by the testing method in JIS A-1321 was less than a half of those for conventional rigid polyurethane foams.
The foams produced by the process of this invention exhibit not only an excellent property of low smoke-generation, but also light weight, high strength, excellent thermal insulation and dimensional stability which essentially belong to the properties of general rigid polyurethane foams. Therefore, the foams of this invention can be widely applied to constructural material, thermal insulating material and lightweighted structural material either alone or in a sandwich or a laminated structure with colored iron plates, zinc plated iron plates, gypsum boards, asbestos slate boards and sheets of paper.
This invention will be illustrated by referring to examples, but the invention will by no means be restricted by the examples. In the examples "parts" means "parts by weight".
In the Examples that follow, Crude MDI is a crude product of diphenylmethane diisocyanate containing 31% of isocyanate groups; Polyol A is a polyether-polyol of a hydroxyl value of 450 prepared by adding propylene oxide to sucrose as an initiator, and Polyol B is a polyether-polyol of a hydroxyl value of 500 prepared by adding propylene oxide to sorbit as an initiator; Silicone oil is a silicone surfactant (SH-193 supplied from Toray Silicone Co.); Methyl cellulose is a product prepared by substituting about 30% of the hydroxyl groups in cellulose by methoxyl groups and a 2% aqueous solution thereof possesses a viscosity of 100 poise (at 20°C), the particle size being approximately 60 mesh; Potato starch is a commercially available starch which is then dried for 3 hours at 120°C (the particle size being about 270 mesh): Corn starch is commercially available starch which is then dried for 3 hours at 120°C (the particle size being about 270 mesh); Wheat starch is a commercially available starch which is then dried for 3 hours at 120°C (the particle size being about 270 mesh); and the ratio in chemical equivalents is the ratio of the number of chemical equivalents of polyisocyanate to the number of chemical equivalents of the substances that react with the polyisocyanate (exclusive of glucose polymers and derivatives thereof).
Physical properties of the foams obtained were determined as follows: the apparent density by ASTM D 1622-63, the flammability by ASTM D 1692-68, the smoke-generation coefficientCA by JIS A 1321 (dimensions of test specimens being 15 × 220 × 220 mm) and friability by ASTM C 421-61.
BRIEF EXPLANATION OF DRAWINGS
FIG. 1 shows the relation between amounts in percentage by weight of methyl cellulose added and the smoke-generation coefficient (CA). FIGS. 2 and 3 show the relation between amounts in percentages by weight of starch added and the smoke-generation coefficient (CA).
Curve A: Curve expressing the smoke-generation coefficients when the ratio in chemical equivalents is 1.05.
Curve B: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 2.00.
Curve C: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 3.00.
Curve D: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 1.05.
Curve E: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 3.00.
Curve F: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 4.00.
Curve G: Curve expressing the smoke-generation coefficient when the ratio in chemical equivalents is 1.05.
EXAMPLES 1 THROUGH 11
Raw materials itemized in Table 1 were weighed in a 1 liter polyethylene beaker which, after vigorous agitation for 20 sec. with a cage-like mixer (3,400 rpm), were foamed in a wooden box, to obtain foamed matter.
COMPARISON EXAMPLES 1 THROUGH 3
Raw materials itemized in Table 1 were treated in the same manner as in Examples 1 through 11, and foams were obtained.
                                  Table 1                                 
__________________________________________________________________________
              Example                          Comparison                 
                                               example                    
Item          1  2  3  4  5  6  7  8  9  10 11 1  2  3                    
__________________________________________________________________________
Reaction mixture                                                          
(in parts)                                                                
Crude MDI     115                                                         
                 115                                                      
                    115                                                   
                       164                                                
                          219                                             
                             219                                          
                                219                                       
                                   328                                    
                                      328                                 
                                         328                              
                                            328                           
                                               115                        
                                                  219                     
                                                     328                  
Polyol A      100                                                         
                 100                                                      
                    100                                                   
                       100                                                
                          100                                             
                             100                                          
                                100                                       
                                   100                                    
                                      100                                 
                                         100                              
                                            100                           
                                               100                        
                                                  100                     
                                                     100                  
Silicone oil  1  1  1  1  1  1  1  1  1  1  1  1  1  1                    
Triethylenediamine                                                        
              0.5                                                         
                 0.5                                                      
                    0.5                                                   
                       0.5                                                
                          0.5                                             
                             0.5                                          
                                0.5                                       
                                   0.5                                    
                                      0.5                                 
                                         0.5                              
                                            0.5                           
                                               0.5                        
                                                  0.4                     
                                                     0.3                  
Potassium acetate                                                         
              0  0  0  0  0  0  0  5.0                                    
                                      5.0                                 
                                         5.0                              
                                            0  0  2.0                     
                                                     5.0                  
Dibutyl tin dilaurate                                                     
              0.1                                                         
                 0.1                                                      
                    0.1                                                   
                       0.1                                                
                          0.1                                             
                             0.1                                          
                                0.1                                       
                                   0.1                                    
                                      0.1                                 
                                         0.1                              
                                            0.1                           
                                               0.1                        
                                                  0.1                     
                                                     0.1                  
Trichloromonofluoro-                                                      
              35 35 35 35 35 35 35 80 80 80 80 35 62 80                   
methane                                                                   
Tris(2-chloroethyl)                                                       
              10 10 10 10 10 10 10 10 10 10 10 10 10 10                   
phosphate                                                                 
              14 30 46 55 19 41 65 27 58 92 93 0  0  0                    
Methylcellulose                                                           
              (5%)                                                        
                 (10%)                                                    
                    (15%)                                                 
                       (15%)                                              
                          (5%)                                            
                             (10%)                                        
                                (15%)                                     
                                   (5%)                                   
                                      (10%)                               
                                         (15%)                            
                                            (15%)                         
                                               (0%)                       
                                                  (0%)                    
                                                     (0%)                 
Ratio in chemical                                                         
equivalent    1.05                                                        
                 1.05                                                     
                    1.05                                                  
                       1.50                                               
                          2.00                                            
                             2.00                                         
                                2.00                                      
                                   3.00                                   
                                      3.00                                
                                         3.00                             
                                            3.00                          
                                               1.05                       
                                                  2.00                    
                                                     3.00                 
Physical properties                                                       
of foam                                                                   
Apparent density(lb/ft.sup.3)                                             
              1.8                                                         
                 1.9                                                      
                    1.9                                                   
                       1.9                                                
                          1.9                                             
                             1.9                                          
                                2.0                                       
                                   1.9                                    
                                      1.9                                 
                                         1.9                              
                                            *  1.8                        
                                                  1.9                     
                                                     1.9                  
Flammability  ** ** ** ** ** ** ** ** ** **    ** ** **                   
C.sub.A       27 18 14 18 38 30 25 46 47 46    50 50 48                   
__________________________________________________________________________
 Remarks:                                                                 
   *Shrinkage                                                             
  **Self-extinguishment
It is seen from the results that the property of smoke-generation was decreased with the increase in the added amount of methyl cellulose when the ratio in chemical equivalent was 1.05, and that the effect to reduce smoke-generation diminished as the ratio in chemical equivalent of rigid polyurethane foams grew large, as shown in the table. When the amount of methyl cellulose exceeded 20%, the remarkably increased viscosity of the raw materials made agitation difficult, and uniform foams could not be sometimes obtained.
EXAMPLES 12 THROUGH 13
In place of the methyl cellulose in Example 3 above, fine crystalline powders of sodium carboxymethyl cellulose and cellulose (particle size of both of the compounds was about 100 mesh) were used respectively. Foams produced in the same process gave results shown in Table 2. The CA values of both foams were less than a half of those for conventional rigid polyurethane foams.
COMPARISON EXAMPLES 4 THROUGH 7
Methyl cellulose in Example 3 above was replaced by a polyhydroxyl alcohol or a succharide which was solid at room temperature, such as, sucrose, pentaerythrit, mannit and glucose. In neither case could the smoke-generating property be effectively reduced. Results are shown in Table 2.
EXAMPLE 14
In the process according to Example 3 above, polyol A was replaced by polyol B. With the ratio in chemical equivalent being 150 and use of 15% of methyl cellulose foams were prepared in the same manner. Results obtained are shown in Table 2. The CA value of the product was less than 1/3 of those of conventional rigid polyurethane foams.
EXAMPLE 15
In the process according to Example 3 above, tris(2-chloroethyl)phosphate (10 parts) was removed from the raw materials with other ingredients remaining unchanged. The foam prepared from the mixture showed the properties as seen in Table 2.
From the results, it is seen that even an inflammable rigid polyurethane foam can be made low smoke-generating by adding methyl cellulose to the raw materials.
                                  Table 2                                 
__________________________________________________________________________
           Example         Comparison example                             
Item       12  13  14  15  4   5   6   7                                  
__________________________________________________________________________
Reaction mixture                                                          
(in parts)                                                                
Crude MDI  115 115 126 115 115 115 115 115                                
Polyol A   100 100     100 100 100 100 100                                
Polyol B           100                                                    
Silicone oil                                                              
           1   1   1   1   1   1   1   1                                  
Triethylene-                                                              
           0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5                                
diamine                                                                   
Dibutyl tin                                                               
dilaurate  0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1                                
Trichloromono-                                                            
fluoromethane                                                             
           35  35  35  35  35  35  35  35                                 
Tris(2-chloroethyl)                                                       
phosphate  10  10  10  0   10  10  10  10                                 
Methylcellulose                                                           
           0   0   46  46                                                 
                   (15%)                                                  
                       (15%)                                              
Sodium carboxymethyl                                                      
           46                                                             
cellulose  (15%)                                                          
Microcrystalline                                                          
               46                                                         
powders of     (15%)                                                      
cellulose                                                                 
                           46                                             
Sucrose                    (15%)                                          
                               46                                         
Pentaerythrit                  (15%)                                      
                                   46                                     
Mannit                             (15%)                                  
                                       46                                 
Glucose                                (15%)                              
Ratio in chemical                                                         
           1.05                                                           
               1.05                                                       
                   1.05                                                   
                       1.05                                               
                           1.05                                           
                               1.05                                       
                                   1.05                                   
                                       1.05                               
equivalent                                                                
Physical properties                                                       
of foam                                                                   
Apparent density                                                          
           1.9 1.9 1.9 1.8 2.2 2.1 2.2 2.0                                
(lb/ft.sup.3)                                                             
Flammability                                                              
           **  **  **  *** **  **  **  **                                 
C.sub.A    22  25  15  15  40  41  39  37                                 
__________________________________________________________________________
 Remarks:                                                                 
  **Self-extinguishment                                                   
 *** Burning
EXAMPLE 16
A mixture consisting of the followng components was foamed in the same manner as in Example 1, to obtain a foam.
______________________________________                                    
Crude MDI                  115                                            
Polyol A                   100                                            
Silicone oil               1                                              
Triethylenediamine         1.0                                            
Dibutyl tin dilaurate      0.1                                            
Trichloromonofluoromethane 55                                             
Tris(2-chloroethyl)phosphate                                              
                           10                                             
Methyl cellulose           24.5                                           
Potato starch              24.5                                           
Ratio in chemical equivalent                                              
                           1.05                                           
______________________________________
Apparent density was 2.0 lb/ft3, flammability property was self-extinguishment, and CA was 18.
COMPARISON EXAMPLES 8 THROUGH 10
The materials shown in Table 3 were treated in the same manner as Example 1 to obtain foams.
EXAMPLES 17 THROUGH 31
The materials shown in Table 3 were treated to obtain a foam in the same manner as in Example 1.
                                  Table 3                                 
__________________________________________________________________________
           Compar.             Compar.                                    
           Example                                                        
                Example        Example                                    
                                    Example                               
Item       8    17 18 19 20 21 9    22 23 24 25 26                        
__________________________________________________________________________
Reaction mixture                                                          
(in parts)                                                                
Crude MDI  115  115                                                       
                   115                                                    
                      115                                                 
                         115                                              
                            115                                           
                               328  328                                   
                                       328                                
                                          328                             
                                             328                          
                                                328                       
Polyol A   100  100                                                       
                   100                                                    
                      100                                                 
                         100                                              
                            100                                           
                               100  100                                   
                                       100                                
                                          100                             
                                             100                          
                                                100                       
Silicone oil                                                              
           1    1  1  1  1  1  2    2  2  2  2  2                         
Triethylenediamine                                                        
           1.0  1.0                                                       
                   1.0                                                    
                      1.0                                                 
                         1.0                                              
                            1.0                                           
                               0    0  0  0  0  0                         
Potassium acetate                                                         
           0    0  0  0  0  0  4    4  4  4  4  4                         
Dibutyl tin dilaurate                                                     
           0.1  0.1                                                       
                   0.1                                                    
                      0.1                                                 
                         0.1                                              
                            0.1                                           
                               0.2  0.2                                   
                                       0.2                                
                                          0.2                             
                                             0.2                          
                                                0.2                       
Trichloromonofluoro-                                                      
methane    35   45 55 55 57 60 90   100                                   
                                       105                                
                                          110                             
                                             115                          
                                                120                       
Tris(2-chloroethyl)                                                       
phosphate  10   10 10 10 10 10 20   20 20 20 20 20                        
Potato starch                                                             
           0    14 31 49 70 94 0    29 62 100                             
                                             143                          
                                                191                       
           (0%) (5%)                                                      
                   (10%)                                                  
                      (15%)                                               
                         (20%)                                            
                            (25%)                                         
                               (0%) (5%)                                  
                                       (10%)                              
                                          (15%)                           
                                             (20%)                        
                                                (25%)                     
Ratio in chemical                                                         
equivalent 1.05 1.05                                                      
                   1.05                                                   
                      1.05                                                
                         1.05                                             
                            1.05                                          
                               3.00 3.00                                  
                                       3.00                               
                                          3.00                            
                                             3.00                         
                                                3.00                      
Physical properties                                                       
of foam                                                                   
Apparent density                                                          
(lb/ft.sup.3)                                                             
           1.8  1.9                                                       
                   1.8                                                    
                      1.9                                                 
                         1.9                                              
                            1.9                                           
                               1.9  2.0                                   
                                       1.9                                
                                          1.9                             
                                             1.9                          
                                                1.9                       
Flammability                                                              
           **   ** ** ** ** ** **   ** ** ** ** **                        
C.sub.A    50   35 22 16 15 15 51   44 38 33 31 30                        
Friability (%)                                                            
           30   20 13 13 11 6  78   76 74 74 67 53                        
__________________________________________________________________________
                               Compar.                                    
                               Example                                    
                                    Example                               
                       Item    10   27 28 29 30 31                        
__________________________________________________________________________
                    Reaction mixture                                      
                    (in parts)                                            
                    Crude MDI  433  433                                   
                                       433                                
                                          433                             
                                             433                          
                                                433                       
                    Polyol A   100  100                                   
                                       100                                
                                          100                             
                                             100                          
                                                100                       
                    Silicone oil                                          
                               3    3  3  3  3  3                         
                    Triethylenediamine                                    
                               0    0  0  0  0  0                         
                    Potassium acetate                                     
                               6    6  6  6  6  6                         
                    Dibutyl tin dilaurate                                 
                               0.3  0.3                                   
                                       0.3                                
                                          0.3                             
                                             0.3                          
                                                0.3                       
                    Trichloromonofluoro-                                  
                    methane    110  120                                   
                                       125                                
                                          130                             
                                             135                          
                                                141                       
                    Tris(2-chloroethyl)                                   
                    phosphate  30   30 30 30 30 30                        
                    Potato starch                                         
                               0    36 77 125                             
                                             177                          
                                                238                       
                               (0%) (5%)                                  
                                       (10%)                              
                                          (15%)                           
                                             (20%)                        
                                                (25%)                     
                    Ratio in chemical                                     
                    equivalent 4.00 4.00                                  
                                       4.00                               
                                          4.00                            
                                             4.00                         
                                                4.00                      
                    Physical properties                                   
                    of foam                                               
                    Apparent density                                      
                               1.9  1.8                                   
                                       1.9                                
                                          1.9                             
                                             1.9                          
                                                2.0                       
                    (lb/ft.sup.3)                                         
                    Flammability                                          
                               **   ** ** ** ** **                        
                    C.sub.A    55   53 53 51 51 50                        
                    Friability (%)                                        
                               85   83 80 79 70 61                        
__________________________________________________________________________
 Remark:                                                                  
 **Self-extinguishment
In Comparison Examples 8 through 10 and Examples 17 through 31, flammability and the smoke-generating property were determined with those rigid polyurethane foams prepared in each example which had approximately an equal apparent density of 1.9 lb/ft3. It was observed from the results that the smoke-generating property was decreased with the increase in the amount of potato starch added when the ratio in chemical equivalents was 1.05, and that the effect of adding potato starch on the decrease in the smoke-generating property becomes less marked for rigid polyurethane foams of a larger ratio in chemical equivalents, as is obvious in Table 3 and FIG. 2. FIG. 2 shows the relation between the amount of starch added and the smoke-generation coefficient in rigid polyurethane foams of apparent density about 1.9 lb/ft3 ; Curves D, E and F correspond to the ratio in chemical equivalents 1.05, 3.00 and 4.00, respectively. The smoke-generation coefficients are larger on Curve E than on Curve D, and larger on Curve F than on Curve E, as is readily seen from the figure. When the amount of starch used exceeds 30%, it may be impossible that a mixture of raw materials can be agitated owing to much increased viscosity to produce uniform rigid polyurethane foams.
COMPARISON EXAMPLE 11
The raw materials shown in Table 4 were treated to obtain a foam in the same manner as in Example 1.
EXAMPLES 32 THROUGH 36
The raw materials shown in Table 4 were treated to obtain foams in the same manner as in Example 1.
              Table 4                                                     
______________________________________                                    
           Compar.                                                        
                  Example                                                 
           Example                                                        
Item         11       32     33   34   35   36                            
______________________________________                                    
Reaction mixture                                                          
(in parts)                                                                
Crude MDI    115      115    115  115  115  115                           
Polyol A     100      100    100  100  100  100                           
Silicone oil 1        1      1    1    1    1                             
Triethylene-                                                              
diamine      0.5      0.5    0.5  0.5  0.5  0.5                           
Dibutyl tin                                                               
dilaurate    0.1      0.1    0.1  0.1  0.1  0.1                           
Trichloromono-                                                            
fluromethane 25       27     30   32   33   35                            
Tris(2-chloroethyl)                                                       
phosphate    10       10     10   10   10   10                            
Potato starch                                                             
             0        13     29   46   65   88                            
             (0%)     (5%)   (10%)                                        
                                  (15%)                                   
                                       (20%)                              
                                            (25%)                         
Ratio in chemical                                                         
equivalent   1.05     1.05   1.05 1.05 1.05 1.05                          
Physical properties                                                       
of foam                                                                   
Apparent density                                                          
(lb/ft.sup.3)                                                             
             3.2      3.2    3.1  3.1  3.1  3.0                           
Flammability **       **     **   **   **   **                            
C.sub.A      52       38     31   24   22   21                            
______________________________________                                    
 Remark:                                                                  
 ** Self-extinguishment
As is seen in Table 4, even when foams were made denser to an apparent density of about 3.1 lb/ft3, the smoke-generating property was found to decrease with the increase in amount of potato starch added, as it was the case with the foams of apparent density about 1.9 lb/ft3 illustrated in FIG. 3.
EXAMPLES 37 THROUGH 42
Foams were prepared from the raw materials which contained corn starch or wheat starch in place of potato starch in preceding Comparison Example 17 and the ratio in chemical equivalents was 1.05. Results are shown in Table 5. The values of CA are lower than those of conventional foams.
EXAMPLES 43 THROUGH 45
Using polyol B, instead of polyol A, foams were prepared as in Example 17. Results are shown in Table 5. The CA values are lower than those of conventional foams.
EXAMPLES 46 THROUGH 48
Foams were prepared in the same manner as in Example 17 except tris(2-chloroethyl) phosphate (10 parts).
Results are shown in Table 5.
It is seen that the rigid polyurethane foams, even if they are burning grade according to ASTM D 1692-68, become low smoke-generating by adding an adequate amount of starch.
                                  Table 5                                 
__________________________________________________________________________
Example                                                                   
            37 38 39 40 41 42 43 44 45 46 47 48                           
__________________________________________________________________________
Reaction mixture                                                          
(in parts)                                                                
Crude MDI   115                                                           
               115                                                        
                  115                                                     
                     115                                                  
                        115                                               
                           115                                            
                              126                                         
                                 126                                      
                                    126                                   
                                       115                                
                                          115                             
                                             115                          
Polyol A    100                                                           
               100                                                        
                  100                                                     
                     100                                                  
                        100                                               
                           100                                            
                              0  0  0  100                                
                                          100                             
                                             100                          
Polyol B    0  0  0  0  0  0  100                                         
                                 100                                      
                                    100                                   
                                       0  0  2                            
Silicone oil                                                              
            1  1  1  1  1  1  1  1  1  1  1  1                            
Triethylenediamine                                                        
            1.5                                                           
               1.5                                                        
                  1.5                                                     
                     1.5                                                  
                        1.5                                               
                           1.5                                            
                              1.5                                         
                                 1.5                                      
                                    1.5                                   
                                       1.0                                
                                          1.0                             
                                             1.0                          
Dibutyl tin                                                               
dilaurate   0.1                                                           
               0.1                                                        
                  0.1                                                     
                     0.1                                                  
                        0.1                                               
                           0.1                                            
                              0.1                                         
                                 0.1                                      
                                    0.1                                   
                                       0.1                                
                                          0.1                             
                                             0.1                          
Trichloromono-                                                            
fluoromethane                                                             
            45 55 57 45 55 57 46 55 58 42 47 53                           
Tris(2-chloroethyl)                                                       
phosphate   10 10 10 10 10 10 10 10 10 0  0  0                            
Potato starch                                                             
            0  0  0  0  0  0  15 33 74 14 29 68                           
                              (5%)                                        
                                 (10%)                                    
                                    (20%)                                 
                                       (5%)                               
                                          (10)                            
                                             (20%)                        
Corn starch 14 31 70 0  0  0  0  0  0  0  0  0                            
            (5%)                                                          
               (10%)                                                      
                  (20%)                                                   
Wheat starch                                                              
            0  0  0  14 31 70 0  0  0  0  0  0                            
                     (5%)                                                 
                        (10%)                                             
                           (15%)                                          
Ratio in chemical                                                         
equivalent  1.05                                                          
               1.05                                                       
                  1.05                                                    
                     1.05                                                 
                        1.05                                              
                           1.05                                           
                              1.05                                        
                                 1.05                                     
                                    1.05                                  
                                       1.05                               
                                          1.05                            
                                             1.05                         
Physical properties                                                       
of foam                                                                   
Apparent density                                                          
            1.9                                                           
               1.9                                                        
                  1.9                                                     
                     1.9                                                  
                        2.0                                               
                           2.0                                            
                              1.9                                         
                                 1.9                                      
                                    1.9                                   
                                       1.8                                
                                          1.9                             
                                             1.9                          
(lb/ft.sup.3)                                                             
Flammability                                                              
            ** ** ** ** ** ** ** ** ** ***                                
                                          ***                             
                                             ***                          
C.sub.A     36 24 17 33 21 17 35 25 16 32 21 15                           
__________________________________________________________________________
 Remarks:                                                                 
  ** Self-extinguishment                                                  
 *** Burning

Claims (4)

What is claimed is:
1. In a low smoke generating rigid polyurethane obtained by heating (A) a polyisocyanate, (B) a polyol having three or more hydroxy groups and a hydroxyl value of 100 and more than 100, and (C) a blowing agent, the improvement which comprises said ingredients (A), (B), and (C) being present in a ratio of chemical equivalents of 1 to 2 parts of ingredient (A) for 1 part of ingredients (B) and (C) combined which react with said ingredient (A), and mixed with at least one member selected from the group consisting of alkyl cellulose, carboxymethyl cellulose, acetyl starch, nitro starch and carboxymethyl starch in the form of powders in an amount exceeding 5% by weight of the composition.
2. The foam according to claim 1, in which a phosphoric ester, a metal oxide, or mixture thereof is used as a flame retardant.
3. The foam according to claim 2, in which the flame retardant is used in an amount of 10% by weight of the polyol.
4. In a process for preparing rigid polyurethane foam by mixing a polyisocyanate, a polyol having more than three hydroxy groups and a hydroxyl value equal to or greater than 100, and blowing agents, the improvement which comprises adjusting the ratio in chemical equivalent of polyisocyanate to the polyol and blowing agent which react with the polyisocyanate in the range between 2 : 1 and 1 : 1, and adding a polymer selected from the group consisting of alkyl cellulose, carboxymethyl cellulose, acetyl starch, nitro starch and carboxymethyl starch in the form of powders in an amount exceeding 5% by weight of the composition to the reaction mixture.
US05/464,633 1973-11-14 1974-04-26 Process for preparing low smoke-generating rigid polyurethane foam Expired - Lifetime US3956202A (en)

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JA48-128077 1973-11-14
JP12807773A JPS5542092B2 (en) 1973-11-14 1973-11-14
JP742582A JPS5622892B2 (en) 1973-12-22 1973-12-22
JA49-2582 1974-12-30

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Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4052526A (en) * 1975-02-19 1977-10-04 General Electric Company Intumescent fire retardant material and article
FR2347391A1 (en) * 1976-04-06 1977-11-04 Grace W R Ltd POLYURETHANE FOAM WITH IMPROVED WATER-WETTING ABILITY, AND PROCESS FOR PREPARATION
US4098729A (en) * 1974-04-08 1978-07-04 Th. Goldschmidt Ag Process of producing cross-linked urethane-group comprising foams of open-cell structure
US4156759A (en) * 1978-01-16 1979-05-29 Krause Milling Company Polyurethane foams containing stabilized amylaceous materials
US4197372A (en) * 1978-01-16 1980-04-08 Krause Milling Company Semi-flexible polyurethane foams containing amylaceous material and process for preparing same
US4205136A (en) * 1978-02-21 1980-05-27 Bridgestone Tire Company Limited Process for producing a rigid polyurethane foam having excellent flame retardance and low-smoke development
US4211849A (en) * 1974-04-08 1980-07-08 Th. Goldschmidt Ag Process of producing cross-linked urethane-group comprising foams of open-cell structure
US4230822A (en) * 1978-10-10 1980-10-28 W. R. Grace & Co. Flame-retardant polyurethane foams
US4237182A (en) * 1978-11-02 1980-12-02 W. R. Grace & Co. Method of sealing interior mine surface with a fire retardant hydrophilic polyurethane foam and resulting product
US4291129A (en) * 1980-06-25 1981-09-22 Patrick James. Crehan Composition and a method for controlling reaction pressures during the foaming process resulting in an easily flame retarded foam-in place insulation
DE3106246A1 (en) * 1981-02-20 1982-09-02 Maizena Gmbh, 2000 Hamburg MOLDING FOR THICKNESS FILLED POLYURETHANE FOAM
WO1983002120A1 (en) * 1981-12-08 1983-06-23 Kennedy, Richard, B. Polyurethane foams and processes for preparation
US4452920A (en) * 1981-05-20 1984-06-05 Joubert & Joubert Proprietary Limited Flexible polyurethane foams having junction modifying particulate additives
US4458034A (en) * 1978-05-12 1984-07-03 Wm. T. Burnett & Co., Inc. Flame retardant, char-forming, flexible polyurethane foams
USRE31757E (en) * 1980-06-25 1984-12-04 Patrick J. Crehan Composition and a method for controlling reaction pressures during the foaming process resulting in an easily flame retarded foam-in place insulation
US20050267278A1 (en) * 2004-05-26 2005-12-01 Danisco A/S Polyurethane containing a polyol composition comprising a highly branched polysaccharide, mix and process for preparation thereof
WO2006040333A1 (en) 2004-10-15 2006-04-20 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
US20060122355A1 (en) * 2004-10-15 2006-06-08 O'connor James Derivatized highly branched polysaccharide and a mix for production of polyurethane thereof
US20060241199A1 (en) * 2004-10-15 2006-10-26 Danisco A/S Foamed isocyanate-based polymer, a mix and process for production thereof
WO2010079202A2 (en) 2009-01-09 2010-07-15 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
AT507849A3 (en) * 2009-01-22 2011-08-15 Eurofoam Gmbh FOAM ELEMENT WITH INCLUDED CELLULOSE
US8906497B2 (en) 2009-01-22 2014-12-09 Eurofoam Gmbh Foam element with hydrophilic substances incorporated in it
US20180030245A1 (en) * 2014-07-18 2018-02-01 Johns Manville Spray foams containing non-halogenated fire retardants
CN114031763A (en) * 2021-09-30 2022-02-11 南京林业大学 Cellulose polyether polyol, preparation method and application thereof, and preparation method of cellulose polyether polyol polyurethane foam

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Cited By (34)

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US4098729A (en) * 1974-04-08 1978-07-04 Th. Goldschmidt Ag Process of producing cross-linked urethane-group comprising foams of open-cell structure
US4211849A (en) * 1974-04-08 1980-07-08 Th. Goldschmidt Ag Process of producing cross-linked urethane-group comprising foams of open-cell structure
US4052526A (en) * 1975-02-19 1977-10-04 General Electric Company Intumescent fire retardant material and article
FR2347391A1 (en) * 1976-04-06 1977-11-04 Grace W R Ltd POLYURETHANE FOAM WITH IMPROVED WATER-WETTING ABILITY, AND PROCESS FOR PREPARATION
US4156759A (en) * 1978-01-16 1979-05-29 Krause Milling Company Polyurethane foams containing stabilized amylaceous materials
US4197372A (en) * 1978-01-16 1980-04-08 Krause Milling Company Semi-flexible polyurethane foams containing amylaceous material and process for preparing same
US4205136A (en) * 1978-02-21 1980-05-27 Bridgestone Tire Company Limited Process for producing a rigid polyurethane foam having excellent flame retardance and low-smoke development
US4458034A (en) * 1978-05-12 1984-07-03 Wm. T. Burnett & Co., Inc. Flame retardant, char-forming, flexible polyurethane foams
US4230822A (en) * 1978-10-10 1980-10-28 W. R. Grace & Co. Flame-retardant polyurethane foams
US4237182A (en) * 1978-11-02 1980-12-02 W. R. Grace & Co. Method of sealing interior mine surface with a fire retardant hydrophilic polyurethane foam and resulting product
US4291129A (en) * 1980-06-25 1981-09-22 Patrick James. Crehan Composition and a method for controlling reaction pressures during the foaming process resulting in an easily flame retarded foam-in place insulation
USRE31757E (en) * 1980-06-25 1984-12-04 Patrick J. Crehan Composition and a method for controlling reaction pressures during the foaming process resulting in an easily flame retarded foam-in place insulation
DE3106246A1 (en) * 1981-02-20 1982-09-02 Maizena Gmbh, 2000 Hamburg MOLDING FOR THICKNESS FILLED POLYURETHANE FOAM
US4452920A (en) * 1981-05-20 1984-06-05 Joubert & Joubert Proprietary Limited Flexible polyurethane foams having junction modifying particulate additives
WO1983002120A1 (en) * 1981-12-08 1983-06-23 Kennedy, Richard, B. Polyurethane foams and processes for preparation
US4400475A (en) * 1981-12-08 1983-08-23 Patrick James Crehan Polyurethane foams and processes for preparation
US20050267278A1 (en) * 2004-05-26 2005-12-01 Danisco A/S Polyurethane containing a polyol composition comprising a highly branched polysaccharide, mix and process for preparation thereof
US7151121B2 (en) 2004-05-26 2006-12-19 Danisco A/S Polyurethane containing a polyol composition comprising a highly branched polysaccharide, mix and process for preparation thereof
WO2006040333A1 (en) 2004-10-15 2006-04-20 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
US20060122355A1 (en) * 2004-10-15 2006-06-08 O'connor James Derivatized highly branched polysaccharide and a mix for production of polyurethane thereof
US20060122286A1 (en) * 2004-10-15 2006-06-08 O'connor James Foamed isocyanate-based polymer, a mix and process for production thereof
US20060241199A1 (en) * 2004-10-15 2006-10-26 Danisco A/S Foamed isocyanate-based polymer, a mix and process for production thereof
US7465757B2 (en) 2004-10-15 2008-12-16 Danisco A/S Foamed isocyanate-based polymer, a mix and process for production thereof
WO2010079202A2 (en) 2009-01-09 2010-07-15 Danisco A/S A foamed isocyanate-based polymer, a mix and process for production thereof
US8735460B2 (en) 2009-01-09 2014-05-27 DuPont Nutrition BioScience ApS Foamed isocyanate-based polymer, a mix and process for production thereof
AT507849B1 (en) * 2009-01-22 2011-09-15 Eurofoam Gmbh FOAM ELEMENT WITH INCLUDED CELLULOSE
AT507849A3 (en) * 2009-01-22 2011-08-15 Eurofoam Gmbh FOAM ELEMENT WITH INCLUDED CELLULOSE
US8906497B2 (en) 2009-01-22 2014-12-09 Eurofoam Gmbh Foam element with hydrophilic substances incorporated in it
AT507850A3 (en) * 2009-01-22 2015-12-15 Eurofoam Gmbh FOAM ELEMENT WITH HYDROPHILES INSERTED IN IT
AT507850B1 (en) * 2009-01-22 2016-01-15 Eurofoam Gmbh FOAM ELEMENT WITH HYDROPHILES INSERTED IN IT
US20180030245A1 (en) * 2014-07-18 2018-02-01 Johns Manville Spray foams containing non-halogenated fire retardants
US10870984B2 (en) * 2014-07-18 2020-12-22 Johns Manville Spray foams containing non-halogenated fire retardants
CN114031763A (en) * 2021-09-30 2022-02-11 南京林业大学 Cellulose polyether polyol, preparation method and application thereof, and preparation method of cellulose polyether polyol polyurethane foam
CN114031763B (en) * 2021-09-30 2023-12-22 南京林业大学 Cellulose polyether polyol, preparation method and application thereof, and preparation method of cellulose polyether polyol polyurethane foam

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